Backport "Merge PR #6728: FIX(Client): bug with talking UI options" t…

…o 1.5.x (#6732)

src/mumble/LookConfig.cpp

@@ -299,7 +299,7 @@ void LookConfig::themeDirectoryChanged() {
 }
 
 void LookConfig::on_qcbAbbreviateChannelNames_stateChanged(int state) {
-	bool abbreviateNames = state == Qt::Checked;
+	bool abbreviateNames = (state == Qt::Checked) || (state == Qt::PartiallyChecked);
 
 	// Only enable the abbreviation related settings if abbreviation is actually enabled
 	qcbAbbreviateCurrentChannel->setEnabled(abbreviateNames);